1 PTHREAD_GETSCHEDPARAM(3C)                         Standard C Library Functions
   2 
   3 
   4 
   5 NAME
   6        pthread_getschedparam, pthread_setschedparam - access dynamic thread
   7        scheduling parameters
   8 
   9 SYNOPSIS
  10        cc -mt [ flag... ] file... -lpthread [ library... ]
  11        #include <pthread.h>
  12 
  13        int pthread_getschedparam(pthread_t thread, int *restrict policy,
  14             struct sched_param *restrict param);
  15 
  16 
  17        int pthread_setschedparam(pthread_t thread, int policy,
  18             const struct sched_param *param);
  19 
  20 
  21 DESCRIPTION
  22        The pthread_getschedparam() and pthread_setschedparam() functions allow
  23        the scheduling policy and scheduling parameters of individual threads
  24        within a multithreaded process to be retrieved and set. Supported
  25        policies are :
  26 
  27        SCHED_OTHER
  28                       traditional time-sharing scheduling class
  29 
  30 
  31        SCHED_FIFO
  32                       real-time class: run to completion
  33 
  34 
  35        SCHED_RR
  36                       real-time class: round-robin
  37 
  38 
  39        SCHED_IA
  40                       interactive time-sharing class
  41 
  42 
  43        SCHED_FSS
  44                       fair-share scheduling class
  45 
  46 
  47        SCHED_FX
  48                       fixed priority scheduling class
  49 
  50 
  51 
  52        See pthreads(5). The affected scheduling parameter is the
  53        sched_priority member of the sched_param structure.
  54 
  55 
  56        The pthread_getschedparam() function retrieves the scheduling policy
  57        and scheduling parameters for the thread whose thread ID is given by
  58        thread and stores those values in policy and param, respectively. The
  59        priority value returned from pthread_getschedparam() is the value
  60        specified by the most recent pthread_setschedparam() or
  61        pthread_create() call affecting the target thread, and does not reflect
  62        any temporary adjustments to its priority as a result of any priority
  63        inheritance or ceiling functions. The pthread_setschedparam() function
  64        sets the scheduling policy and associated scheduling parameters for the
  65        thread whose thread  ID is given by thread to the policy and associated
  66        parameters provided in policy and param, respectively.
  67 
  68 
  69        If the pthread_setschedparam() function fails, no scheduling parameters
  70        will be changed  for the target thread.
  71 
  72 RETURN VALUES
  73        If successful, the pthread_getschedparam() and pthread_setschedparam()
  74        functions return  0. Otherwise, an error number is returned to indicate
  75        the error.
  76 
  77 ERRORS
  78        The pthread_getschedparam() and pthread_setschedparam() functions will
  79        fail if:
  80 
  81        ESRCH
  82                 The value specified by thread does not refer to an existing
  83                 thread.
  84 
  85 
  86 
  87        The pthread_setschedparam() function will fail if:
  88 
  89        EINVAL
  90                  The value specified by policy or one of the scheduling
  91                  parameters associated with the scheduling policy policy is
  92                  invalid.
  93 
  94 
  95        EPERM
  96                  The caller does not have the appropriate permission to set
  97                  either the scheduling parameters or the scheduling policy of
  98                  the specified thread.
  99 
 100 
 101 ATTRIBUTES
 102        See attributes(5) for descriptions of the following attributes:
 103 
 104 
 105 
 106 
 107        +--------------------+-------------------+
 108        |  ATTRIBUTE TYPE    |  ATTRIBUTE VALUE  |
 109        +--------------------+-------------------+
 110        |Interface Stability | Committed         |
 111        +--------------------+-------------------+
 112        |MT-Level            | MT-Safe           |
 113        +--------------------+-------------------+
 114        |Standard            | See standards(5). |
 115        +--------------------+-------------------+
 116 
 117 SEE ALSO
 118        pthread_attr_init(3C), sched_getparam(3C), sched_get_priority_max(3C),
 119        sched_get_priority_max(3C), sched_get_priority_min(3C),
 120        sched_setparam(3C), sched_getscheduler(3C), sched_setscheduler(3C),
 121        attributes(5), pthreads(5), standards(5)
 122 
 123 
 124 
 125                                  April 1, 2008       PTHREAD_GETSCHEDPARAM(3C)